1. Field of the Invention
The present invention relates to a video signal recording and reproducing apparatus for a digital video cassette tape recorder which is capable of judging the transmission amount of the digital video data inputted from a digital video source, the type of video tape, and whether of not the tape is recorded in accordance with the judgment result, thus automatically controlling a recording mode and a reproducing mode.
2. Description of the Conventional Art
Generally, a digital video cassette tape recorder (DVCR) records a digital video signal outputted from a certain digital broadcast source such as an advanced television system, a cable decoder, and a satellite broadcast signal receiver onto a video tape magnetic recording medium and to reproduces the recorded digital video signal.
The DVCR includes an integrated receiver decoder (IRD) (not shown), which is referred to as an exclusive receiver, for receiving digital video signals from a digital broadcast source, for thus recording the received digital video signal onto a video tape using a video signal processing means and for reproducing the recorded digital signal.
A digital VHS VCR (DVHS) is one type of DVCR directed to recording digital signals onto a video tape in a recording pattern as shown in FIG. 1 and reproducing the recorded digital signal.
Here, one track of the tape includes a first preamble data region which is recorded at the start portion of each track and indicates the start of the track, a sub-code region which indicates certain information referred to the recording/reproducing operation, a main data region which includes a video information, and a second preamble data region which is recorded at the end portion of each track and indicates the end of the track.
The above-mentioned digital signal is received through the IRD (not shown). A format unit formats the video signal. A signal processor modulates the signal, and then the signal is recorded onto a video tape in the pattern as shown in FIG. 1. The signal reproduced from the video tape is demodulated by the signal processor, and formatted by the format unit and then is outputted. Here, the rotation speed of a head drum in the recording/reproducing mode is 1800 rpm which is the same as in the conventional VHS format VCR.
Here, the digital tape, that is, a super VHS (SVHS) tape, is generally used, which has a recording wavelength of 0.8 .mu.m rather than the 1.4 .mu.m wavelength of the normal VHS type tape so as to more effectively record/reproduce a large amount of digital information thereon without recording/reproducing loss and noise as compared with the analog video signal.
However, because the recording pattern of the digital video signal recording and reproducing apparatus for a conventional DVHS-VCR is completely different from that of an analog broadcast, as shown in FIG. 1, only the high density tape is used.
That is, when recording/reproducing the digital video signal, since the DVHS-VCR is directed to recording on and reproducing from only the S-VHS tape which is a high density tape, when using the common VHS video tape, which is intended for recording and reproducing an analog signal in the DVHS-VCR, it is impossible to record and reproduce therewith since the recording density is low.
The recording density difference is referred to the recordable wavelength of the tape. Generally, in case of the common VHS video tape, the recordable wavelength is about 1.4 .mu.m, and the recordable wavelength of the S-VHS tape is about 0.8 .mu.m.
Therefore, when recording the digital video data, it is possible to record as much as one track as shown in FIG. 1 on the S-VHS tape having a recordable wavelength of 0.8 .mu.m, the recordable region on which the data can be recorded is limited with the VHS tape having a low density of a recordable wavelength of about 1.4 .mu.m, so that it is impossible to record the digital data in only one track of the S-VHS tape of the common VHS tape.
Namely, in order to record and reproduce the digital signal in the prior art, a high density video tape should be used.
The above-mentioned problem causes lack of compatibility with the common video tape of the widely used analog type VCR.
Therefore, when a user records and reproduces using a normal tape in the DVHS-VCR, and there is no display on the screen, the user may think there is a problem in the system. So as to overcome the above-mentioned problem, when the system is equipped with the VHS recording prevention apparatus, and the user inserts a normal tape and selects a recording mode, the recording operation may not be operational, and then the user may think there is a problem in the system. The above-mentioned problem may cause inconvenience in properly using the system and is confusing to the user.
In addition, when recording the digital data on the high density tape intended for the digital data, if the amount of the digital data is substantially small, it is wasteful to record the digital data on the high density video tape.